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August 17, 2005

Autoimmune reaction tied to diabetic neuropathy

by Sam Savage

By David Douglas

NEW YORK (Reuters Health) - Individuals with diabetes often
develop a problem with the nerves that control internal body
functions, known as diabetic autonomic neuropathy. Autonomic
neuropathy is a common and serious complication of diabetes,
one that increases the risk of death. Effective treatments are
limited by a lack of any clear understanding of what causes the
problem.

Now, European researchers report that so-called self or
autoantibodies that attack the body's own nerve cells are
associated with the subsequent development of autonomic
neuropathy in diabetic patients.

Among a group of type 1 or insulin-dependent diabetic
patients, more than half had autonomic nerve autoantibodies and
these patients had a greater than sevenfold increased risk of
developing autonomic neuropathy, Dr. Viktoria Granberg told
Reuters Health.

These observations suggest that autonomic neuropathy in
type 1 diabetes may have an autoimmune background, Granberg of
Malmo University Hospital in Sweden and colleagues conclude.

Their study is published in this month's issue of Diabetes
Care.

After a baseline examination covering autonomic nerve
function, the 41 type 1 diabetic patients participating in the
study were examined three more times over the course of 13 to
14 years. At the third examination, at about 6 years, blood
samples were drawn and analyzed for autonomic nerve
autoantibodies.

A total of 23 patients (56 percent) showed evidence of
autonomic nerve autoantibodies. Among this group, the frequency
of at least one abnormal cardiac autonomic nerve function test
at the third examination (74 percent) and fourth examination
(71 percent) was significantly higher than in the type 1
diabetics without these antibodies (39 percent and 25 percent).
No such differences were seen at the first and second
examinations.

Over the follow-up period, subjects with autonomic nerve
autoantibodies showed a relative risk of developing cardiac
neuropathy some 7.5 times that of the other subjects, according
to the investigators.

These findings suggest to the team that autonomic nerve
autoantibodies play a key role in the development and
progression of nerve dysfunction in individuals with type 1
diabetes.